FORGET last year's silage, now is the time to improve future profit margins and reduce the amount of visible waste in clamps, which can be as much as £4500 for a 500-tonne clamp.

According to Chris Totten, Biotal regional business manager in Scotland, on average more than 10% of grass silage harvested is wasted every year with the big problem being that the true cost tends to be under-estimated.

"We calculate that waste silage costs £90/tonne, so for a 500 tonne clamp with 10% waste, the annual bill would be £4500." he said adding that it's a cost farmers seem to accept even though there is no reason why so much silage is wasted.

Mr Totten said direct cost is made up of two main elements, with the first being the physical cost of growing, harvesting and ensiling the crop which is estimated at £30/t freshweight.

“To this must be added the cost of replacing the feed value. A tonne freshweight at 30% dry matter and 10.7MJ ME/kgDM would supply 3210MJ, enough to produce 605 litres. Producing this milk from concentrates, assuming a feed rate of 0.45kg/l would require an additional 272kg of concentrates, which at £220/t, would cost £60 to replace each tonne of wasted freshweight."

He added: “To this can be added the cost of ‘invisible’ waste, the feed that looks OK but is below the visible waste layer and has reduced nutrients from increased yeast and mould activity causing dry matter losses from heat and protein breakdown as well as reduced palatability resulting in poorer production from forage and increased costs. And then there is the labour cost of removing the waste."

Mr Totten said that on a 500t clamp with 10% waste, 50 tonnes of product will have to be taken off the clamp and disposed of. If it takes 10 minutes per day to remove the waste for a 200-day winter, this adds up to 2000 minutes, or 33 hours. This is time that could be more usefully spent doing more constructive tasks on most farms.

“Waste is optional, so set out now to make a clamp with zero visible waste your objective. Success will be a combination of planning and attention to detail at silage making time.”

To reduce the risk of wastage, he advised rapid and thorough fermentation to preserve physical forage and feed value. A crop and condition specific inoculant, formulated for the dry matter of the crop being ensiled is also advisable which should be applied at the full rate and to every load. Leaving even a small pocket of untreated material can be sufficient to develop a pocket of waste in the clamp, Mr Totten said.

In addition, he pointed out that the clamp should be filled carefully and rolled thoroughly, paying close attention to the shoulders. “Then cover the clamp using a true oxygen barrier such as Silostop. You have to keep oxygen out and barrier films are the most effective way to do this. The whole clamp must be covered and weighted down comprehensively. Once the clamp is sheeted, keep off it to avoid the sheeting being damaged which would allow air to enter the clamp."